net/mlx5: Free IRQs in shutdown path

Some platforms require IRQs to be free'd in the shutdown path. Otherwise
they will fail to be reallocated after a kexec.

Fixes: 8812c24d

 ("net/mlx5: Add fast unload support in shutdown flow")
Signed-off-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>